1. Field
The present disclosure relates to a scan driving device and a driving method thereof, and more particularly, to a scan driving device using an N-type oxide thin film transistor and a driving method thereof.
2. Description of the Related Technology
Recently, in the display apparatus industry, technologies relating to high-speed driving and a large-sized screen have received attention. Since an amorphous silicon thin film transistor (amorphous-Si TFT) has low mobility and low current driving capacity, the amorphous-Si TFT is not suitable for implementing in high-speed driving and a large-sized screen. Since a low temperature poly-silicon (LTPS) thin film transistor has high mobility, but has a low crystallization speed of the LTPS and a defect problem is generated during an LTPS crystallization process, it is difficult to implement a large-sized screen. Since an N-type low temperature polysilicon thin film transistor has excellent current driving capacity, but is sensitive to noise, a P-type low temperature polysilicon thin film transistor which is insensitive to noise is frequently used.
Recently, an oxide thin film transistor (Oxide TFT), which has oxide such as amorphous indium-gallium-zinc-oxide (IGZO), zinc-oxide (ZnO), and titanium oxide (TiO) as an active layer, has been recognized as a substitute element of the amorphous silicon thin film transistor and the low temperature polysilicon thin film transistor. The oxide thin film transistor has high mobility as compared with the amorphous silicon thin film transistor and has uniformity as an element characteristic which is similar to the amorphous silicon thin film transistor. Further, the oxide thin film transistor may be applied to various kinds of display apparatuses such as a transparent display apparatus, vehicle glass, building glass, and goggles, due to its transparent and flexible characteristics.
Since the characteristics and kind of material of the N-type oxide thin film transistor are excellent as compared with the characteristics and kind of material of the P-type oxide thin film transistor, the N-type oxide thin film transistor is suitable for implementing the high-speed driving and the large-sized screen of the display apparatus. The N-type oxide thin film transistor has a negative threshold voltage characteristic.
Scan driving devices of display apparatuses which have been developed in the related art are P-type scan driving devices using the P-type low temperature polysilicon thin film transistor, which has aa positive threshold voltage characteristic. Accordingly, it is difficult to apply the N-type oxide thin film transistor having the negative threshold voltage characteristic to the P-type scan driving device which has been developed in the related art.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.